Do a tag search here for polymono, you might have to play around with the tags a bit I'm techniphobic so aren't much use but I know they're there. If you go a way back in general discussions you'll find "The Struggling mono thread".
If you want to go off the forum for support I write a blog (link in signature). Check out the earlier threads, when I was struggling with polymono.
You ask are you definitely not polyamorous? And can you evolve towards it. These are good questions to be asking but I don't think you can really know at this stage.
Many of us (me included), try out polyamory just because we are in a relationship with a polyamorous person. We think it will make it easier but in my experience and observation of others it doesn't. I think you first have to work through all the emotions that you're currently going through before it will really become clear whether you could "evolve into polyamory". I don't think evolve is a very good word because it puts polyamory on a higher level than monogamy and I don't agree that it is necessarily.
I started out mono and have moved to a what I call being "poly friendly". For me that means that while I'm open to it I'm not at all looking and I'm very content with my relationship as it is. My partner has another love.
Read, participate in the forum and ask specific questions, you'll get plenty of support.
This will be a challenging time but if you open your heart and your mind, also a very rewarding one.
Last edited by sage; 02-19-2011 at 11:31 AM.